1. Field of the Invention
The present invention relates to an airbag of an automatic vehicle, and more particularly to an airbag system of an automotive vehicle adapted to guide a deployed direction of airbag deployed toward automotive vehicle occupants to an advantageous direction in coping with a slant collision when an automotive vehicle eccentrically collides in left/right directions, thereby protecting the automotive vehicle occupants in the collision.
2. Description of the Prior Art
Generally, seat belts are provided in an automotive vehicle as a protective means to prevent automotive vehicle occupants from being injured or killed when an automotive vehicle collides, along with airbags.
The airbag is stowed in an uninflated and folded condition in a covered compartment, each located on the steering wheel or behind the instrument panel, above the glove compartment and before the rear seats, as a safety device for protecting the automotive vehicle occupants in a collision.
In other words, the airbags mentioned above as stowed in from of the front seats include, as illustrated in FIG. 1, a driver seat airbag module 2 installed in the center of the steering wheel and a front seat occupant airbag module 4 stowed in the front dashboard 3, where both airbags 2 and 4 are respectively connected to an electronic control unit 5 and a wire harness 6 each disposed underneath the center floor console and the electronic control unit 5 is in turn connected to the wire harness 6 to receive power from a battery 7.
The electronic control unit 5 is mounted therein with acceleration sensors (not shown) for detecting changes of speed (or velocity) of an automotive vehicle. The acceleration sensors detect change of decelerating speed of the running automotive vehicle, and if the detected change of the decelerated speed exceeds a predetermined level, in other words, in the event of a collision, the acceleration sensors send electric signals to the airbag modules 2 and 4 respectively.
Meanwhile, the drive seat airbag module 2 is mounted in the center of the steering wheel 1, as illustrated in FIG. 2, and interior construction of the driver seat airbag module 2 is shown in FIG. 3 for illustrating a sectional view taken along line III--III in FIG. 2. In other words, the driver seat airbag module 2 includes a pad cover 8 cut and opened when an airbag is deployed via an cut-off part 8a at the center thereof, an airbag 9 accommodated in the pad cover 8, being folded, and an inflator 10 connected to a margin of a bottom surface of the airbag 9 and filled with an explosive, a priming charge, a gas forming agent, a diffuser screen (all not shown) and the like.
When there is a change above a predetermined level in the deceleration of an automotive vehicle in the event of a collision, the acceleration sensors at the electronic control unit 5 detect the change and send electric signals to the driver seat airbag module 2. The power applied to the inflator 10 of the airbag module 2 ignites the explosive and the priming charge in a matter of milliseconds to burn the gas forming agent. Nitric gas generated in the process of burning the gas forming agent is discharge outside of the inflator 10 through the diffuser screen to thereafter be infused into the airbag 9. As a result thereof, the airbag 9 accommodated in the pad cover 8, being folded, is expanded and breaks the cut-off part 8a at the pad cover 8 to be deployed into position in front of the vehicle occupant and to effectively cushion the occupant against injury-causing impact with interior structures of the vehicle.
Meanwhile, the inflator at the driver seat airbag module 2 includes an upper body unit 11 and a lower body unit 12, as illustrated in FIG. 4, where the upper body unit 11 is formed at its periphery with a plurality of gas-discharging vent holes 13, each disposed at an equal radiating distance therebetween, and the upper body unit 11 is also formed at both opposite margins with tethers 14 of flexible material such as fabric, one end of each tether being fixed to the margin while the other end of each tether being stitched and fixed to an inner surface of the airbag 9.
The nitric gas generated from the inflator 10 in the event of a collision is discharged outside of the inflator 10 through the plurality of vent holes provided at the upper body unit 11 and is infused into the airbag 9.
The airbag 9 expanded by the infused nitric gas is caused to expand and burst widely through the central pad cover 8 at the steering wheel 1 into position in front of the driver to effectively protect him or her from impact.
At this time, the tether 14 serves to restrain the airbag 9 from expanding to an extreme distance when the airbag 9 is expanded by the gas generated from the inflator 10, thereby preventing the occupant from a so-called back slap phenomenon where face of an occupant receives an abrasion due to expanded airbag. Unexplained reference numeral 16 in the drawing is a back supporter of a driver.
However, there is a problem in the airbag according to the prior art thus constructed in that the airbag 9 according to the conventional airbag system cannot fully cope with left/right slanted collision because the airbag 9 is expanded and deployed evenly in front of a driver 15 even in the event of a left/right slanted collision, let alone the head-on collision with an obstacle 18 (which include vehicles and various kinds of popping obstacles).
In other words, when a running vehicle 17 collides in eccentrically left/right directions, the airbag 9 which is uniformly expanded and deployed in front of the driver 15 regardless of head-on collision or left/right eccentric collisions cannot effectively cushion the driver against injury.